#include <stdio.h>
#include <stdlib.h>
#define LEN sizeof(struct Student)

struct Student{
    long num;
    float score;
    struct Student *next;
}

int n;
struct Student *creat(void){
    struct Student *head;
    struct Student *p1,*p2;
    n=0;
    p1=p2=(struct Student *)malloc(LEN);
    scanf("%ld,%f",&p1->num,&p1->score);
    head=NULL;
    while(p1->num!=0){
        n=n+1;
        if(n==1) head=p1;
        else p2->next=p1;
        p1=(struct Student *)malloc(LEN);
        scanf("%ld,%f",&p1->num,&p1->score);
    }
    p2->next=NULL;
    return head;
}